Apparatus for forming two component yarns



y 23, 1957 1.. v. CANCIO ETAL APPARATUS FOR FORMING TWO COMPONENT YARNS Filed Aug. 25, 1965 United States Patent 3,320,633 APPARATUS FOR FORMING TWO COMPONENT YARNS Leopoldo Vicente Cancio and Robert Douglas Soutter, both of Chattanooga, Tenn., assignors to E. I. du Pont de Nemours and Company, Wilmington, Del., 21 corporation of Delaware Filed Aug. 25, 1965, Ser. No. 482,412 3 Claims. (Cl. 18-8) This invention relates to improved synthetic textile filaments and yarns and more particularly to an improved spinneret assembly for producing composite filaments.

Filaments consisting of two or more components are known in the art. Such filaments are produced by ex truding the different components from the spinneret in side-by-side relationship or in an eccentrically disposed sheath-core arrangement. The components are usually so selected that they have different shrinkage characteristics when the filament is heated in the relaxed state with the result that a crimped fiber can be produced.

Another approach is described in Tanner, US. Patent 3,117,906, where side-by-side filaments are spun together, woven into a fabric, and then when the fabric is scoured the components split apart to give fine-denier elements. This produces an improved fabric which is closely similar and nearly identical to silk in properties and aesthetic qualities while having the usual functional characteristics associated with a synthetic polymer fabric.

Tanner illustrates a spinneret assembly used to produce side-by-side filaments. Difficulties are encountered in using this assembly and other similar packs in that there is no clear interface; i.e., one polymer flows around and forms a discontinuous partial sheath. This leads to processing difficulties in that this tends to shed small fragments or slivers of the fiber, which are known as deposits, downstream of the spinneret. These deposits tend to cling to processing equipment, e.g., yarn guides, jets, traverse mechanism, etc., ultimately causing breakdown of the yarn line. Such deposits do not form when there is a generally planar interface between the two polymers.

When it is desired that the elements split apart, the partial sheathing prevents proper splitting during the scouring step and the desired aesthetic characteristics of the fabric are not developed. It is essential that there be a generally planar interface between the side-by-side elements when it is desired that they split apart during later processing steps.

Another difliculty encountered with the spinneret assembly described in Tanner is that it requires very precisely angled holes so that the intersection of the two polymers is identical in all of the filaments issuing from a single spinneret assembly. It is well known that it is much simpler to drill holes straight through a piece of metal than to intersect two holes blindly in the central portion of a piece of metal.

Accordingly, the major object of this invention is an improved spinneret assembly which will produce side-byside elements within a filament where there is a generally planar interface between the two polymers. Another object is a spinneret assembly which is relatively simple and less costly to make.

These and other objects are accomplished by the spinneret assembly of this invention which includes a spinneret plate with one or more nozzles, each nozzle having .an orifice on the downstream face of the spinneret plate and a large entrance hole in the back or upstream face of the spinneret plate, a meter plate juxtaposed to the back of the spinneret plate, a plurality of expansion chambers positioned above each entrance hole, the expansion chambers located in the downstream face of the meter plate adjacent 3,320,633 Patented May 23, 1967 the spinneret plate, sources of supply located upstream of said expansion chambers, and a metering hole connecting each expansion chamber to a source of supply.

In the accompanying drawings:

FIGURE 1 is a cross-sectional view of a composite filament illustrating the undesirable partial sheathing of one polymer around another;

FIGURE 2 is a cross-sectional view of a composite filament having the desired, generally planar interface; and

FIGURE 3 is a cross section of the spinneret assembly of the present invention.

As illustrated in FIGURE 3, a spinneret plate 12 and a meter plate 14 are attached to a sandholder 16 by bolt 18, thus forming the spinneret assembly 10. Frequently, it is desirable to align these plates with locating pins, not illustrated. No gaskets are used since sealing is accomplished by the use of lapped faces on all mating surfaces. In the spinneret plate 12 there are a number of spinning nozzles 20; two are illustrated. Each spinneret nozzle has an orifice 22 at the downstream face of the spinneret plate and a large diameter entrance hole 24 at the upstream face of the spinneret plate. Directly above each entrance hole 24 are two expansion chambers 26 and 27, since the spinneret assembly illustrated is for spinning two-component side-by-side filaments. If more than two polymers or two segments are desired, additional expansion chambers would be used. These expansion chambers 26 and 27 are in the downstream face of meter plate 14. A metering hole 28 connects expansion chamber 26 with a source of polymer supply. Similarly, metering hole 29 connects expansion chamber 27 with a second source of supply. Supply chamber 30 is an annular cavity in the upstream face of meter plate 14. Supply chamber 32 is a similar but smaller annular cavity concentric with supply chamber 30. The details of construction of the supply chambers are not pertinent to this invention and can be the annular cavities described or just a number of circular holes.

In the sandholder 16 there is a central circular cavity 34. Surrounding it is an annular cavity 36. Directly below annular cavity 36, groove 38 is cut into the face of the sandholder 16. A plurality of holes similar to hole 40 connect annular cavity 36 with grove 38. Similarly, a plurality of holes similar to holes 42 and 43 conmeet the central cavity 34 with annular groove 44.

If it, of course, recognized that it is possible to eliminate either the supply chambers 30 and 32 or the grooves 38 and 4 in certain designs. Another variation is to eliminate all the supply chambers and grooves (30, 32, 38 and 44) and have holes 40 feed directly to metering holes 28 and holes 42 and 43 feed directly to metering holes 29. The means for supply polymer is described next.

In operation, polymer F is supplied to the central cavity 34. Normally, filtration means such as sand or screens, or a combination of the two are inserted in the central cavity 34. Polymer F leaves the central cavity 34 from the bottom through a plurality of holes 42 and 43 which feed the annular groove 44. Annular groove 44 is in matched relationship with the supply chamber 32. Polymer F is then metered to each indivdual position or spining nozzle by a metering hole 29. Since a certain amount of polymer is supplied by a positive displacement pump, polymer is forced through the small diameter metering hole 29 in the form of a high velocity jet. When this jet reaches the expansion chamber 27, which has a relatively large diameter, the velocity of the polymer is reduced and the polymer now moves at a low rate of speed from the expansion chamber into the entrance hole 24.

In a similar manner, polymer S is supplied to annular cavity 36, through holes 40 into annular cavity 38 and supply chamber 30, then through metering hole 28 into for mixing, particularly in the high viscosity polymers used to form synthetic filaments. The two sideby-side polymer streams are then brought to an increasing veolcity by the shape of the bottom of the spinneret nozzle and issue from the orifice 22 in the form of a high velocity jet.

. However, at this point there is no tendency for the polymers to intermix since they already have assumed the desired side-by-side relationship.

In the pack illustrated in schematic form by Tanner, it has been found necessary to use a metering restriction for each polymer stream. The place that seems logical to do this, both from a manufacturing viewpoint and a polymer flow viewpoint, is to meter just before the polymers join together. Unfortunately, this generates two high velocity jets which impinge upon one another and cause interreaction and does not give a generally planar interface between the two polymers. It is found that partial sheathing results. A typical non-round cross section is shown in FIGURE 1 where elements of polymer F partially encircle polymer S. The same phenomena occurs with round filaments. Difiiculties are encountered in processing these filaments after they are spun. In addition, poor fabric aesthetics are achieved due to the failure to obtain the desired splitting between the two elements.

FIGURE 2 shows the filament cross section obtained with the spinneret assembly of this invention. There is a generally planar interface between polymer F and polymer S. No deposits are formed during the processing of these filaments and the desired fabric aesthetics are obtained.

While the specific spinneret assembly described is for two-component side-by-side filaments, it is obvious that there could be more than two components or two polymers used. The number of and placement of the metering holes and the expansion chambers would have to be revised accordingly. Further, the pack illustrated provides for a circular pattern of the spinning nozzles 20 on the face of the spinneret plate 12, and the various holes and cavities in the meter plate 14 and spinneret plate 12 and sandholder 16 are located accordingly. It is possible to use the same basic concept with a spinneret which has the spinning nozzles aligned in rows. In such a design the cavities in the sandholder and the various distribution channels would have to be revised to supply polymer to the metering holes at the proper locations. However, no matter which pattern is used, circular or rows, the essential requirement of this invention is that a metering hole be followed by an expansion chamber so that metered polymers, when joined together, are moving at a relatively slow velocity to prevent any partial sheathing or encircling of one polymer around another.

While the supply and distribution channels and cavities are illustrated in the sandholder and the meter plate, it may be desirable to use a separate distribution plate between the sandholder and the meter plate.

It is to be understood that the foregoing description is by way of example only and that various modifications and changes may be made Without departing from the spirit of the invention and the scope of the following claims.

What is claimed is:

1. A spinneret assembly for producing composite filaments from two or more polymers comprising: a spinneret plate having a downstream face and an upstream face, said spinneret plate having one or more nozzles 10- cated therein, each of said nozzles having an orifice at the downstream face of said spinneret plate and a large entrance hole at the upstream face of said spinneret plate; a meter plate having a downstream face and an upstream face, the downstream face of said meter plate being juxtaposed to the upstream face of said spinneret plate; a plurality of expansion chambers located in the downstream face of said meter plate, two or more of said expansion chambers being positioned above and opening directly into each of said entrance holes; a plurality of supply sources located upstream of said expansion chambers; a metering jet connecting each expansion chamber to a supply source; and means for supplying polymer to each of said supply sources.

2. A spinneret assembly for producing composite filaments from two or more polymers comprising: a spinneret plate having a downstream face and an upstream face, said spinneret plate having one or more nozzles located therein, each of said nozzles having an orifice .at the downstream face of said spinneret plate and a large entrance hole at the upstream face of said spinneret plate; a meter plate having a downstream face and an upstream face, the downstream face of said meter plate being juxtaposed to the upstream face of said spinneret plate; a plurality of expansion chambers located in the downstream face of said meter plate, two or more of said expansion chambers being positioned above and opening directly into each of said entrance holes; a plurality of supply chambers located in the upstream face of said meter plate; a metering jet connecting each expansion chamber to a supply chamber; and means for supplying polymer to each of said supply chambers.

3. A spinneret assembly for producing composite filaments from two or more polymers comprising: a spinneret plate having a downstream face and an upstream face, said spinneret plate having one or more nozzles located therein, each of said nozzles having an orifice at the downstream face of said spinneret plate and a large entrance hole at the upstream face of said spinneret plate; a meter plate having a downstream face and an upstream face, the downstream face of said meter plate being juxtaposed to the upstream face of said spinneret plate; a plurality of expansion chambers located in the downstream face of said meter plate, two or more of said expansion chambers being positioned above and opening directly into each of said entrance holes; a sandholder having a downstream face and an upstream face, the downstream face of said sandholder being juxtaposed to the upstream face of said meter plate; a plurality of supply chambers located in the downstream face of said sandholder; a metering jet connecting each expansion chamber to a supply chamber; and means for supplying polymer to each of said supply chambers.

References Cited by the Examiner UNITED STATES PATENTS 2,792,122 5/1957 Munch et a1 188 XR 2,971,219 2/1961 Hill 18-8 2,988,420 6/ 1961 Ryan et al. 3,095,607 7/1963 Cobb; 3,117,362 1/1964 Breen. 3,117,906 1/1964 Tanner 161-406 XR 3,176,342 4/ 1965 Davis 188 FOREIGN PATENTS 865,843 4/1961 Great Britain. 902,690 8/ 1962 Great Britain.

WILLIAM J. STEPHENSON, Primary Examiner. 

1. A SPINERET ASSEMBLE FOR PRODUCING COMPOSIT FILAMENTS FROM TWO OR MORE POLYMERS COMPRISING: A SPINNERET PLATE HAVING A DOWNSTREAM FACE AND AN UPSTREAM FACE, SAID SPINNERET PLATE HAVING ONE OR MORE NOZZLES LOCATED THEREIN, EACH OF SAID NOZZLES HAVING AN ORIFICE AT THE DOWNSTREAM FACE OF SAID SPINNERET PLATE AND A LARGE ENTRANCE HOLE AT THE UPSTREAM FACE OF SAID SPINNERET PLATE; A METER PLATE HAVING A DOWNSTREAM FACE AND AN UPSTREAM FACE, THE DOWNSTREAM FACE OF SAID METER PLATE BEING JUXTAPOSED TO THE UPSTREAM FACE OF SAID SPINNERET PLATE; A PLURALITY OF EXPANSION CHAMBERS LOCATED IN THE DOWNSTREAM FACE OF SAID METER PLATE, TWO OR MORE OF SAID EXPANSION CHAMBERS BEING POSITIONED ABOVE AND OPENING DIRECTLY INTO EACH OF SAID ENTRANCE HOLES; A PLURALITY OF SUPPLY SOURCES LOCATED UPSTREAM OF SAID EXPANSION CHAMBERS; AMETERING JET CONNECTING EACH EXPANSION CHAMBER TO A SUPPLY SOURCE; AND MEANS FOR SUPPLYING POLYMER TO EACH OF SAID SUPPLY SOURCES. 